1 files changed, 10 insertions, 2 deletions
diff --git a/uriloader/exthandler/nsExternalHelperAppService.cpp b/uriloader/exthandler/nsExternalHelperAppService.cpp
index 84dc262561..3577ff2bbf 100644
--- a/uriloader/exthandler/nsExternalHelperAppService.cpp
+++ b/uriloader/exthandler/nsExternalHelperAppService.cpp
@@ -3491,8 +3491,8 @@ void nsExternalHelperAppService::SanitizeFileName(nsAString& aFileName,
   nsAutoString fileName(aFileName);
 
   // Replace known invalid characters.
-  fileName.ReplaceChar(u"" KNOWN_PATH_SEPARATORS, u'_');
-  fileName.ReplaceChar(u"" FILE_ILLEGAL_CHARACTERS, u' ');
+  fileName.ReplaceChar(u"" KNOWN_PATH_SEPARATORS FILE_ILLEGAL_CHARACTERS "%",
+                       u'_');
   fileName.StripChar(char16_t(0));
 
   const char16_t *startStr, *endStr;
@@ -3674,6 +3674,14 @@ void nsExternalHelperAppService::SanitizeFileName(nsAString& aFileName,
     outFileName.Truncate(lastNonTrimmable);
   }
 
+  nsAutoString extension;
+  int32_t dotidx = outFileName.RFind(u".");
+  if (dotidx != -1) {
+    extension = Substring(outFileName, dotidx + 1);
+    extension.StripWhitespace();
+    outFileName = Substring(outFileName, 0, dotidx + 1) + extension;
+  }
+
 #ifdef XP_WIN
   if (nsLocalFile::CheckForReservedFileName(outFileName)) {
     outFileName.Truncate();